Objective: Evaluation of combined morphometry and immunoexpression of cytokeratin 13 (CK13) and cytokeratin 17 (CK17) for cytological identification of superficial oral squamous cells. Study Design: Smears from 11 tongue squamous cell carcinoma patients were processed by liquid-based cytology, stained via the Papanicolaou method and divided into multiple specimens by cell transfer. Morphometric indices, including nuclear area, nuclear perimeter, nuclear circular rate, largest-to-smallest dimension ratio of the nucleus and nucleocytoplasmic ratio, were measured using a computerized analysis system. CK13 and CK17 were detected by immunostaining. Morphometric values were compared between cell populations with distinct staining and immunoexpression patterns. Results: Most orange G-stained superficial cells were negative for CK13 (99.4%) and CK17 (98.6%). For light green-stained superficial cells, loss of CK13 was associated with greater cellular atypia in the nuclear area, nuclear perimeter and nucleocytoplasmic ratio (p < 0.01), while expression of CK17 was related to higher-grade cellular atypia in the same parameters (p < 0.01) as well as the nuclear circular rate (p < 0.05). Conclusion: Immunoexpression of CK13 and CK17 in light green-stained superficial cells was associated with more severe morphological atypia. Combined morphometry and immunoexpression of CK13 and CK17 might be useful for cytological diagnosis of this cell population.